CEA, thought to be a purely carcino-embryonic antigen, has been found to be a complex glycoprotein or family of closely related glycoproteins. The lack of specificity of the CEA test has limited its value as a diagnostic test for cancer. The main objectives of this project are: (a) To define and purify more tumor specific or organ specific antigenic forms of CEA, by analytic and preparative isofocusing. (b) To characterize the antigenic site of CEA, by the use of a number of synthetic glycopeptides of known structure. (c) To use the separated CEAs or the synthetic glycopeptides with the greatest CEA immuno-reactivity, as labeled antigens in the CEA assay system. The assay can then be evaluated as a cancer diagnostic test by testing available sera from patients with cancer and controls and comparing the results of told CEA levels. (d) To develop an animal model for CEA-like antigens. Studies concerning the metabolism and immune response to injected CEA will be performed.